The invention proceeds from a device for conveying insulating glass panes. A device of this type is known from DE 80 27 173 U. Devices of this type are used in that area of production lines for insulating glass panes that handles a semi-finished insulating glass pane composed of two individual glass sheets with insertion between the latter of a spacer frame affixed to the glass sheets. A semi-finished insulating glass pane of this type has an all-round edge gap that is filled with an initially pasty and later hard-setting sealing compound which has the tasks of creating a permanent and strong bond between the individual glass sheets forming the insulating glass pane and of protecting the interior of the insulating glass pane against the ingress of moisture. Thiokols and polyurethane in particular are in use as sealing compound.
For sealing the edge gap of semi-finished insulating glass panes, the production lines contain a sealing station in which the insulating glass panes are sealed by one or more jets which are passed along the sheet edges (DE-C-28 16 427). The device in accordance with the invention is intended above all for use in a sealing station of this type.
The device known from DE-U80 27 173 has a horizontal conveyor with two synchronously driven endless chains arranged parallel to one another and supporting paired and opposite supports and compression blocks. The glass sheets rest with their lower edges on the supports, which only partially grip round the glass sheets from the outer edge side, so that the edge gap remains free. The compression blocks ensure that the glass sheets do not slide down from the supports during conveying and do not slip. To be able to convey glass sheets of differing thickness, one of the conveyor chains is, together with deflection gears around which it passes, movable at right angles to the conveying direction and to the rotation axes of the deflection gears.
To ensure that the glass sheets do not tip over from the horizontal conveyor, a supporting device is provided above the horizontal conveyor, which the glass sheets lean against. In the device known from DE-U-80 27173, a height-adjustable line of supporting rollers supports the glass sheets close to their top edges.
The supports of the known device grip underneath the two individual glass sheets of the insulating glass panes from the outer edge side only partially, thereby leaving free both the edge gap and an strip adjacent to it on the lower edge of the individual glass sheets. This is intended to prevent the horizontal conveyor from picking up any of the pasty sealing compound that has been poured into the edge gap. One drawback of the known device is that the clamping of the glass sheets between the compression blocks can result in splintering at the lower edge of the glass sheet, particularly since the edges of the glass sheets are generally not smooth, but broken and hence irregular. A further drawback is that a sealed insulating glass pane cannot be removed until the clamping effect exerted by the compression blocks has been released by transverse movement of one of the conveyor chains. There is a risk here that the insulating glass pane can slide off the horizontal conveyor.
A considerable advance was achieved with the conveying device known from EP 0 549 648 B1, which has a horizontal conveyor with supporting surfaces on which the glass sheets are conveyed upright. The supporting surfaces are aligned with two planes, are parallel to the conveying direction and form an upward-opening taper. The supporting surfaces, which are preferably designed as toothed belts, support the glass sheets only at the outside of the lower edge of the two glass sheets forming the insulating glass pane. Thanks to the tapered arrangement of the supporting surfaces, the glass sheets tend to center themselves on the horizontal conveyor, which is of advantage for the conveying process. This tendency to self-centering can lead to both glass sheets exerting pressure on the spacer between them. If the spacer is sufficiently strong, which is always the case with spacers formed from metallic hollow sections, there are no problems at all. These problems can however occur in the case of plastic spacers, for example thermoplastic ones, which are not extruded onto one of the glass sheets until immediately before the assembly of the insulating glass pane and first have to set in conjunction with the glass sheets. When these spacers extruded in situ onto a glass sheet are used, the pressure exerted during self-centering onto the spacer can compress the latter and hence reduce the distance between the two glass sheets to less than the required spacing. This danger increases in the case of glass sheets that are thicker and heavier, particularly in the case of laminated glass sheets and glass sheets of structured glass, particularly when these have a sanded bevel at the edge, as this bevel favours drift on the inclined supporting surfaces.
According to the present invention this object is solved by a device for conveying for conveying insulating glass panes slightly inclined from the perpendicular with a horizontal conveyor on which the glass sheets can stand, and with a supporting device extending above and parallel to the horizontal conveyor and defining a pane movement plane by one or a plurality of supporting elements against which can rest the insulating glass panes standing on the horizontal conveyor, in which the horizontal conveyor has supporting surfaces provided at two parallel and synchronously drivable conveying elements, the supporting surfaces being aligned substantially vertical to the pane movement plane, and the distance between the conveying elements being variable, and in which both conveying elements are moveable independently of one another transversely to the pane movement plane. The invention is also directed to an advantageous method aligning the conveying elements in a device according to the present invention by positioning mutually facing edges of the supporting surfaces flush with the two inner and lower glass edges of the respective insulating glass pane.
This object is solved by a device having the features given in claim 1. Advantageous embodiments of the invention form the subject matter of the sub-claims. Claim 14 relates to an advantageous method for operating the device in accordance with the invention.
In the conveying device in accordance with the invention, both conveying elements are movable independently of one another and transverse to the sheet movement plane. This has crucial advantages:
The width and position of the gap between the supporting surfaces at the rear conveying element (closest to the pane movement plane) on the one hand and the supporting surfaces at the front conveying element (which is at a greater distance from the pane movement plane) on the other hand can be closely adapted to the width and position of the edge gap between the two glass sheets of a insulating glass pane. In DE-U-80 27 173, the distance of the conveying elements can be closely adapted only to the thickness of the insulating glass pane overall.
The two glass sheets of the insulating glass pane can be supported over the entire width of their lower edge, i.e. from the outer edge to the inner edge of the respective glass sheet, leaving free the edge gap defined by the inner edges of the two glass sheets. In the device in accordance with DE-U-80 27 173, the glass sheets could only be under-gripped from the outside by a small dimension, identical for thin, light sheets and for thick, heavy ones. Therefore sheets whose outer edges are ground to a bevel practically cannot be supported and conveyed at all. In the case of the device known from EP 0 549 648 B1, both thin, lightweight glass sheets and thick, heavy ones are supported only at their outer edges. Accordingly, whereas in the case of the conveying devices to the prior art the specific load on the supporting surfaces is very high for thick and heavy glass sheets and can lead to considerable wear, with the conveying device in accordance with the invention the specific load does not increase with the thickness of the glass sheets, the result being that the supporting surfaces of the conveying elements are subjected to much less wear.
Glass sheets can also be conveyed without problem when one or both sheets are bevelled at the outer edge.
During the conveying operation, practically no pressure is then exerted on the spacer.
The device in accordance with the invention can also be used for the conveying of stepped insulating glass panes. Stepped insulating glass panes are units where one of the two sheets is larger than the other, so that it projects beyond the other along at least one edge (see EP 0 549 556 B1). If the larger sheet of the insulating glass pane projects beyond the smaller glass sheet along the lower edge, it can be transported on the conveying device in accordance with the invention if at least one of the two conveying elements, preferably the conveying element nearest the pane movement plane, is adjustable not only transverse to the pane movement plane, but also in its height, ideally parallel to the pane movement plane. The height adjustability of a conveying element is known per se for this purpose from EP 0 549 556 B1, but not in combination with the transversely movable conveying elements. Preferably only one of the conveying elements is height-adjustable, i.e. the conveying element nearest the pane movement plane. Height adjustability for the second conveying element can be dispensed with.
In order to closely match the width and position of the gap between the supporting surfaces at the rear conveying element on the one hand and the supporting surfaces at the front conveying element on the other hand to the width and position of the edge gap of a insulating glass pane, it is necessary to know how thick the rear glass sheet in the pane movement plane is and how wide the edge gap is. The width of the edge gap is also referred to as the sheet intermediate space or air space. In an automated production line for insulating glass panes, these dimensions can be entered in a control unit of the device in accordance with the invention right from the order processing stage, e.g. by a machine-readable coded label affixed to the respective glass sheet and containing these dimensions, which is read by a reader integral to the production line before the glass sheet reaches the conveying device in accordance with the invention, such that the conveying elements can be preset by positioning motors to match the dimensions as read. Instead of obtaining the thickness of the rear glass sheet and the width of the edge gap in advance from a data carrier, these two dimensions can be measured in the insulating glass pane production line in which the device in accordance with the invention is incorporated in keeping with the intended purpose, but also by sensors connected to the control unit of the device in accordance with the invention such that said sensors operate the positioning motors intended for transverse movement of the conveying elements in line with the two dimensions measured of the glass sheet and adjust the conveying elements before the glass sheet enters the device in accordance with the invention.
The conveying elements of the device in accordance with the invention can be of various design. They can be two parallel and horizontal lines of synchronously driven rollers on which stand the two glass sheets of a insulating glass pane. More favourable than supporting surfaces that are in rolling contact with the lower edge of the glass sheet are however supporting surfaces that extend in the horizontal conveying direction and pass with the glass sheets through the conveying device, e.g. a series of horizontal supports attached to an endless chain. The best method is however to use as conveying elements belts whose top part is supported by a carrier. A belt of this type offers the glass sheets the largest possible contact surface and can yet leave the edge gap completely free. Since there is no relative movement between the belts and the glass sheets, there is no concern that the glass sheet can run askew in the course of the conveying operation, as for example would be possible with a roller conveyor. Compression blocks or guide rollers acting from the outside on the glass sheets in order to guide them, and in so doing exerting pressure on the spacer, can be dispensed with in accordance with the invention.
It is advantageous to use a driver device in the form of a suction conveyor belt in the supporting unit, said device extending above and parallel to the horizontal conveyor and being drivable synchronously with the conveying elements. A suction conveyor belt of this type, which is disclosed for example in EP 0 549 548 B1 where it has the task of moving the insulating glass pane dependably over a gap in the horizontal conveyor, i.e. over a gap in which a sealing jet is located to fill the edge gap of the insulating glass pane with sealing compound, is in the scope of the present invention a suitable and advantageous means of keeping the insulating glass pane dependably in the pane movement plane without any pressure being exerted on the spacer as a result.
The carrier has preferably a horizontal upper side aligned substantially at right angles to the pane movement plane, on which upper side the top part of the belt slides. To assure good straight running of the belt, guide means are ideally provided that extend in the predetermined conveying direction, e.g. a flat groove in the top of the carrier in which the belt runs under lateral guidance.
If it is intended to reduce the friction between the belt and its carrier, there is the possibility of providing in the carrier a series of rollers arranged close by each other and with parallel axes and at identical height for supporting the top part of the belt.
In order to achieve slip-free conveying using the belts, the latter are preferably toothed belts with the toothing on the underside that pass around gears, at least one of which is driven.